How to select transformer (converter, power supply adaptor) for 110 V USA appliances?

Manufacturers usually print appliance’s parameters on the attached tag, displaying its power in Watts [W]. In that case it’s simple. If the power is for example 245 W, select a transformer that is closest to that value on the available list, adding an extra margin of power for safety. In this example, a 300VA transformer should be selected. Some manufacturers display parameters in Amperes [A]or [Amps] as an electric current required for proper operation; for example 2.7 A or 2.7 Amps. You then need to multiply number of Amperes by 120. In this case 2.7 x 120 = 324. The result represents the approximate power of transformer needed. After adding a safety margin of at least 20%, 400 VA transformer should be selected.

WARNING!

The power of a transformer must always be higher than the power of the apliance connected to that transformer. Otherwise, either unit can sustain serious damage.

WARNING!

Transformerswith a nomina power 1000VAandaboveproducea highinrush current. We recommend usingtheinrush current limiter.